A security method for D2D mode B discovery is disclosed in the embodiments of the present disclosure, in four processes of the D2D mode B discovery service, integrity protection is performed, by adding corresponding parameters, on a discovery response message of a passive terminal, a discovery response message of an active terminal, a query request message sent by the active terminal to the passive terminal, a query response message sent by the passive terminal to the active terminal, and the matching report message of the active terminal. A security system, terminal for D2D mode B discovery and a storage medium are further disclosed in the embodiments of the present disclosure.